SI units: past paper questions
Real questions on si units
The newest 20 of 42 written questions. Open one to see it on the real paper.
- 9702/21 · October/November 2025 · Q2b(ii)[2]
Determine the SI base units of η. base units
See it on the paper → - 9702/23 · October/November 2025 · Q2b(ii)[2]
Determine the SI base units of η. base units
See it on the paper → - 9702/23 · May/June 2025 · Q2b(i)[3]
Calculate m. m = kg (i)
See it on the paper → - 9702/42 · February/March 2025 · Q3b(ii)[2]
Determine the number N of molecules of nitrogen gas. N =
See it on the paper → - 9702/41 · October/November 2024 · Q1b(iii)[5]
Use the gradient and intercept of the line in Fig. 1.1 to determine values for A and B. Give units with your answers. (iii) A = unit
See it on the paper → - 9702/22 · May/June 2024 · Q1a[1]
The list below shows some SI quantities. Underline the quantity that is not an SI base quantity. charge current length time
See it on the paper → - 9702/42 · October/November 2023 · Q1a[1]
Define the radian.
See it on the paper → - 9702/22 · May/June 2023 · Q1a(ii)[1]
Use the answer to (a)(i) to show that the SI base units of pressure are kg m –1 s –2 .
See it on the paper → - 9702/22 · May/June 2023 · Q1b[3]
A horizontal pipe has length L and a circular cross‑section of radius R. A liquid of density ρ flows through the pipe. The mass m of liquid flowing through the pipe in time t is given by m = π(p 2 – p 1 )R 4 ρ t 8kL where p 1 and p 2 are the pressures at the ends of the pipe and k is a constant. Determine the SI base u...
See it on the paper → - 9702/23 · May/June 2023 · Q2a[2]
21% of the volume of the sphere is below the surface of the water. Calculate the density of the sphere. density = kg m −3
See it on the paper → - 9702/41 · May/June 2023 · Q3b(i)[1]
mercury is a suitable liquid
See it on the paper → - 9702/41 · May/June 2023 · Q3b(ii)[2]
water is not a suitable liquid.
See it on the paper → - 9702/41 · May/June 2023 · Q3c(i)[1]
State the boiling temperature, in °C, of the liquid. temperature = °C
See it on the paper → - 9702/41 · May/June 2023 · Q3c(ii)[4]
Determine the specific heat capacity, in J g –1 K –1 , of the liquid. specific heat capacity = J g –1 K –1
See it on the paper → - 9702/41 · May/June 2023 · Q3d[2]
The experiment in (c) is repeated using water instead of the liquid in (c). The mass of liquid used, the power supplied, and the initial temperature are all unchanged. The specific heat capacity of water is approximately twice that of the liquid in (c). The boiling temperature of water is 100 °C. On Fig. 3.2, sketch th...
See it on the paper → - 9702/41 · May/June 2023 · Q4a[2]
State two of the basic assumptions of the kinetic theory of gases.
See it on the paper → - 9702/41 · May/June 2023 · Q4b(i)[2]
Determine an expression for the temperature T of the gas in state X, in terms of n, p and V. Identify any other symbols that you use.
See it on the paper → - 9702/41 · May/June 2023 · Q4b(ii)[3]
On Fig. 4.1, sketch the variation with volume of pressure for the gas as the gas undergoes the three changes. The state X is labelled. Label states Y and Z. 2p X pressure p 0 0 2V V volume Fig. 4.1
See it on the paper → - 9702/41 · May/June 2023 · Q4b(iii)[5]
During the change of state from Y to Z, the increase in internal energy of the gas is U. During the change of state from Z to X, the work done on the gas is W. Complete Table 4.1 to indicate, for each of the three changes of state, the increase in internal energy of the gas, the thermal energy transferred to the gas an...
See it on the paper → - 9702/52 · May/June 2023 · Q2d(i)[1]
Using your answers to (a), (c)(iii) and (c)(iv), determine the values of Y and Z. Include appropriate units. Data: p = (1.01 ± 0.01) × 10 5 Pa k = 1.38 × 10 –23 J K –1 Y = Z =
See it on the paper →
What examiners said
Generally well-answered. However, one misconception that was common in a minority of candidates, warrants mention. Having correctly stated the starting equation pV = NkT, some candidates substituted the change in volume from part (b)(i) as the value of V.
— Examiner report, February/March 2025, 9702/42 Q3(b)(ii) (Cambridge)
The definition of the radian was well known by many candidates. It was important to note that this question asked for the definition of the unit, not the definition of the quantity ‘angle’ in radians. Some weaker candidates defined the radian in terms of the degree to radian conversion.
— Examiner report, October/November 2023, 9702/42 Q1(a) (Cambridge)
The majority of the candidates found it very straightforward to show how the SI base units of pressure are determined.
— Examiner report, May/June 2023, 9702/22 Q1(a)(ii) (Cambridge)
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